Susquehanna River flooding not good for Chesapeake Bay

By Cory Nealon

Near record flooding of the Susquehanna River is expected to hurt water quality in the Chesapeake Bay.

Scientists are especially concerned about underwater grasses, which are important habitat for blue crabs and juvenile fish; and oysters, which cannot move to escape the pollutants and silt the deluge is expected to carry into the bay.

As of Friday, the river was flowing at 775,000 cubic feet per second — the third-highest measurement on record — at the Conowingo dam in Maryland.

The high water level is the result of an unusually wet spring and recent tropical storms, according to the Chesapeake Bay Program, an umbrella group of state and federal agencies that oversees the estuary’s restoration.

As water travels from farms, roads and other surfaces it picks up pollutants that are deposited into the river and, eventually, the bay. Those pollutants, combined with the force of the river flow, is expected to dislodge underwater grasses, especially near the upper parts of the bay.

In addition to providing habitat, underwater grasses improve water quality by soaking up excess nutrients that, left unchecked, often lead to algae blooms.

The floodwater is also expected to bring a layer of silt that will cover hard bottom surfaces where oysters grow. Excess silt prevents oysters, a filter feeder, from eating microscopic food found in water.

While not good news for the bay, the flooding could have been worse.

The peak growing season for underwater grasses occurs during early summer, so the projected damage will be less than if the flooding occurred in June or July. Also, September is not a major spawning period in the bay, so the effect on fish and other marine life should be minimal, the program said.

Scientists expect a majority of the pollution to have worked its way through the bay system by spring. But they said the full affect won’t be known for months or even years.